BaseCrush wafers with the end of a rolling pin or in a food processor. Combine biscuit crumbs, cocoa and icing sugar. Add butter and mix well. Press mixture into base of a 23cm springform cake tin. Bake in oven at 180 degrees celsius for 8-10 minutes. Cool.

Filling
Beat cream cheese, caster sugar and 1 tsp vanilla until smooth and creamy. Add eggs, one at a time, beating well after each addition.

In a separate bowl, mix together cocoa and 1/4 cup sugar. Add oil, remaining vanilla and 1 and 1/2 cups of the cream cheese mixture and stir to combine. Add raspberry jam and flour to remaining cheese mixture and stir to combine.

Pour half of the raspberry mixture over biscuit base. Add half of the chocolate mixture in dollops over the top. Repeat with remaining mixture ending with chocolate dollops on top. Gently swirl with a sharp pointed knife.

Bake for 10 minutes at 180 degrees celsius. Reduce temperature to 120 degrees celsius and bake for a further 55 minutes. Turn oven off and let cheesecake cool with the door slightly ajar. When completely cool, cover with plastic wrap and refrigerate overnight.